Leather does not stain itself, it must have been done by something else. If you have a soft absorbent leather (one that absorbs moisture readily) then anything that has stained will be in the leather ans you cannot clean it out. You can only clean of...
hmmmm the best thing to do is to get some leather cleaner - ask a guy friend with leather seats in their car - they might have some leather cleaner for their seats - that worked for me once. I guess auto part stores might sell leather cleaner too
If you can't touch it it is difficult, maybe you can try to check if it has pores. Fake leather doesn't have pores, it is synthetic, real leather has pores (it is skin after all), and you can see these tiny black specks. I would not risk it. Even if ...